During electron microscopy or ion-beam analysis, a test sample is placed on a sample support. Typically, the sample supports consist of a metal grid, often copper, gold, nickel, or molybdenum. For certain types of analysis, a thin carbon film is typically placed atop the metal grid. The carbon film is very thin, conductive, and often contains holes. When used during cryo-electron microscopy, this holey carbon film allows for analysis of very small specimens or specimens embedded in vitreous ice.
There are several problems with the existing sample support technology. During analysis, the very thin carbon film tends to move or drift due to its lack of thermal and mechanical stability, which degrades the ability to achieve highest resolution images. The holey carbon film is supported by a metal grid, however, the presence of grid bars blocks imaging area and limits the ability to perform tomographic analysis. Thermal instability exists due to coefficient of thermal expansion (CTE) mismatch between the metal grid and the carbon film which may create wrinkles on or tear the carbon film. In addition, since the conductivity of the carbon degrades quickly at very low temperatures, deflection during imaging results due to electron-beam induced charging.
Accordingly, there exists a need in the art for sample supports with improved properties including, but not limited to, minimal drift during analysis by electron microscopy; increased rigidity; and conductivity of the sample support structures, including at low temperatures; and decreased electron charging. The present invention addresses this need.